NSTAR's first flight for 2009 was paired with the second flight of the year for NearSys, Paul Verhage's ARHAB project. Sunday the 3rd was an excellent day for our flights. Based on the wind forecast, we decided we could get some extra sleep and didn't arrive at our launch site at Gretna High School until shortly after 8, planning on a 9am launch. The winds were light from the northwest, so we chose a spot on the southeast corner of the school so we could get a little windbreak from the building in case they came up a little more.
We decided to launch NearSys first, with NSTAR to follow shortly. NearSys had an uneventful fill and was released at 0920 CDT. As I was checking over the NSTAR payloads, I found that the backup beacon was not transmitting. Looking it over, I found that I had accidentally left the GPS/TinyTrak battery pack on overnight and exhausted the batteries. Since I was able to obtain some alkaline batteries from Wayne, we continued on with our launch prep and release the NSTAR balloon at 0934 CDT.
The balloons rose almost straight up from the launch site, owing to the light winds near the surface. After getting on the road, I checked the simplex repeater. Even at 50W I was unable to bring it up. This was a disappointment as we had at least a couple of hams planning to exercise it during the flight. Everything else was working OK and we continued towards Red Oak.
Approaching Red Oak we made contact with Larry N0BKB who came over from Greenfield to chase. Shortly before we reached Red Oak, the NearSys balloon burst at 1049 CDT and 88,157 ft. Not long after, the NSTAR 1500g Kaymont balloon burst at 1058 CDT and 94,659 ft.
We headed north on US 71 from US 34 and then turned east south of Grant. The timing was such we did not expect we could watch both landings, so Wayne KE6DZD, Chuck KD0BWI, and I focused on the NSTAR landing while Paul, Larry, and Doug KA0O chased to the NearSys landing. We were able to see the parachute once the packages were below about 10,000 ft. Around this time, we noticed that the simplex repeater was working again, albeit with a weak signal. The balloon was drifting due south over our county road for the last several minutes of the flight, but instead of coming toward us it dropped almost straight down in front of us about a quarter mile away. The landing was in a hayfield about 150 yds from the road at 1144 CDT.
On inspection, we saw that the coax for the simplex repeater antenna was broken. We used a trailing piece of RG-174 with a HT whip hanging below the payload. It could have broken from the cold, or maybe for some other reason. Next time we'll add another antenna to the same ground plane used for the backup APRS antenna. The balloon still had 900g of material attached, about 60% of the original mass. However, even with that much weight the parachute was observed to be fully open and the line from the chute apex to the balloon did not foul with the stack on the way down.
The descent rates varied rapidly below 9000 ft MSL. I noticed that cumulus clouds had begun to form about 15 minutes before the payloads descended to that altitude, so I suspect there was a lot of vertical air motion (thermals) that the parachute encountered.
Reviewing the photos, we were able to identify about ten where the NearSys balloon was visible. Several excellent photos of downtown Omaha were also taken, as well as of the Platte River valley and of the cumulus clouds as the payloads descended. A flight later this year will experiment with collecting RAW images for better enhancement possibilities – the JPEG compression can result in undesired color or texture artifacts after enhancement.
NearSys balloon as seen by NSTAR. Inset in center is at full camera resolution.
Aerial photos below:
Ground photos below: